At least 100 early childhood centers and school buildings in New York City reported at least one case of COVID-19 by the first day of in-person classes on Sept. 21, The New York Times reports. By Tuesday, 11 more schools and two pre-kindergartens reported cases as well, and nearly all of the buildings were still open. The city’s guidelines only require individual schools to close if there are at least two cases in different classrooms. New York City’s mandated testing program for public schools won’t start until October and students will be tested once a month, which experts say is not enough. “I think the vast majority of schools will have outbreaks, and then bring people back,” Dr. Michael Mina, an assistant professor of epidemiology at Harvard T.H. Chan School of Public Health, said. “Test people, and trace them and bring them back after a week or two. But that is such a disruptive process.” Mayor Bill De Blasio said that classes with shift remotely if the positivity rate in the entire city rises above 3 percent.